Arizona State Sun Devils guard Shaquielle McKissic (40) is helped to his feet after be injured against the Arizona Wildcats in the second half of their NCAA basketball game Saturday, Feb. 7, 2015 in Tempe, Ariz. David Kadlubowski/azcentral sports

Arizona at Arizona State men's basketball

Arizona State Sun Devils guard Shaquielle McKissic (40) is helped to his feet after be injured against the Arizona Wildcats in the second half of their NCAA basketball game Saturday, Feb. 7, 2015 in Tempe, Ariz.
David Kadlubowski/azcentral sports

Arizona Wildcats head coach Sean Miller in the second half of their NCAA basketball game Saturday, Feb. 7, 2015 in Tempe, Ariz. David Kadlubowski/azcentral sports

Arizona at Arizona State men's basketball

Arizona Wildcats head coach Sean Miller in the second half of their NCAA basketball game Saturday, Feb. 7, 2015 in Tempe, Ariz.
David Kadlubowski/azcentral sports

Arizona Wildcats guard Gabe York (1) misses a dunk against Arizona State Sun Devils guard Bo Barnes (33) in the second half of their NCAA basketball game Saturday, Feb. 7, 2015 in Tempe, Ariz. David Kadlubowski/azcentral sports

Arizona at Arizona State men's basketball

Arizona Wildcats guard Gabe York (1) misses a dunk against Arizona State Sun Devils guard Bo Barnes (33) in the second half of their NCAA basketball game Saturday, Feb. 7, 2015 in Tempe, Ariz.
David Kadlubowski/azcentral sports

Arizona State Sun Devils guard Shaquielle McKissic (40) drives to the net against Arizona Wildcats guard Elliott Pitts (24) in the second half of their NCAA basketball game Saturday, Feb. 7, 2015 in Tempe, Ariz. David Kadlubowski/azcentral sports

Arizona at Arizona State men's basketball

Arizona State Sun Devils guard Shaquielle McKissic (40) drives to the net against Arizona Wildcats guard Elliott Pitts (24) in the second half of their NCAA basketball game Saturday, Feb. 7, 2015 in Tempe, Ariz.
David Kadlubowski/azcentral sports

Arizona State Sun Devils forward Savon Goodman (11) drives to the basket against Arizona Wildcats forward Brandon Ashley (21) in the second half of their NCAA basketball game Saturday, Feb. 7, 2015 in Tempe, Ariz. David Kadlubowski/azcentral sports

Arizona at Arizona State men's basketball

Arizona State Sun Devils forward Savon Goodman (11) drives to the basket against Arizona Wildcats forward Brandon Ashley (21) in the second half of their NCAA basketball game Saturday, Feb. 7, 2015 in Tempe, Ariz.
David Kadlubowski/azcentral sports

Arizona State Sun Devils guard Tra Holder (0) plows into Arizona Wildcats forward Rondae Hollis-Jefferson (23) during the first half of their NCAA basketball game on Feb. 7, 2015, in Tempe. David Kadlubowski/azcentral sports

Arizona at Arizona State men's basketball

Arizona State Sun Devils guard Tra Holder (0) plows into Arizona Wildcats forward Rondae Hollis-Jefferson (23) during the first half of their NCAA basketball game on Feb. 7, 2015, in Tempe.
David Kadlubowski/azcentral sports

Arizona State Sun Devils guard Tra Holder (0) looks to pass against the Arizona Wildcats during the first half of their NCAA basketball game on Feb. 7, 2015, in Tempe. David Kadlubowski/azcentral sports

Arizona at Arizona State men's basketball

Arizona State Sun Devils guard Tra Holder (0) looks to pass against the Arizona Wildcats during the first half of their NCAA basketball game on Feb. 7, 2015, in Tempe.
David Kadlubowski/azcentral sports

Arizona State Sun Devils guard Bo Barnes (33) has the ball stripped by Arizona Wildcats forward Stanley Johnson (5) and forward Rondae Hollis-Jefferson (23) during the first half of their NCAA basketball game on Feb. 7, 2015, in Tempe. David Kadlubowski/azcentral sports

Arizona at Arizona State men's basketball

Arizona State Sun Devils guard Bo Barnes (33) has the ball stripped by Arizona Wildcats forward Stanley Johnson (5) and forward Rondae Hollis-Jefferson (23) during the first half of their NCAA basketball game on Feb. 7, 2015, in Tempe.
David Kadlubowski/azcentral sports

The Arizona State Sun Devils take the lead with a basket by ASU forward Savon Goodman (11) against Arizona Wildcats forward Rondae Hollis-Jefferson (23) during the first half of their NCAA basketball game on Feb. 7, 2015, in Tempe. David Kadlubowski/azcentral sports

Arizona at Arizona State men's basketball

The Arizona State Sun Devils take the lead with a basket by ASU forward Savon Goodman (11) against Arizona Wildcats forward Rondae Hollis-Jefferson (23) during the first half of their NCAA basketball game on Feb. 7, 2015, in Tempe.
David Kadlubowski/azcentral sports

Just eight days ago, Bo Barnes was in a similar position. Down one to Oregon in overtime, the Arizona State senior launched a rushed 3-pointer in the final seconds that missed, and the Sun Devils lost on their home court.

Barnes insisted the shot didn't stick with him. He clung to the words of an assistant coach who reminded him to stay confident. "Next shot," the coach had told him. "Keep shooting."

Against No. 6 Arizona on Saturday, that advice paid off. With under a minute left and the shot clock winding down, Barnes curled behind teammate Tra Holder and drilled a 3-pointer from 28 feet, the biggest shot in ASU's shocking 81-78 upset win in front of 10,876 fans at wild Wells Fargo Arena.

For the second time in two years, ASU fans rushed their home court after defeating their rivals from Tucson. Just 34 days ago, UA had defeated ASU 73-49 at the McKale Center. In that contest, the Sun Devils had led for all of 29 seconds. Saturday, they led the entire second half.

With its biggest win of the season, ASU improved to 12-11 and 4-6 in the Pac-12. UA, not only fighting for the conference regular-season crown but a possible top seed in March's NCAA Tournament, dropped to 20-3 and 8-2.

Here's how Barnes' big shot – possibly one of ASU's biggest in the history of this mostly one-sided rivalry – went down: ASU led 72-68 with under a minute to go. The Sun Devils held the ball, looking for a good shot, but with the shot clock under 10 they were running out of options.

Holder, a freshman point guard, dribbled right and Barnes circled behind him.

Holder: "Bo does a great job of filling behind me when I penetrate. He called my name and I trust him."

Barnes: "I saw the shot clock running down so I just tried to get it up there."

Senior forward Jonathan Gilling: "I was like, 'Holy (expletive), what are you doing, Bo? Because I was kind of open in the corner."

Swish.

"Bo was heart-broken with that one he had missed against Oregon," assistant coach Barret Peery said, "so after that shot went in, I was like, 'Wow. There's justice for you right there."'

Nothing over the previous month had suggested this. UA had won six in a row, holding five opponents to 56 or fewer points. The Wildcats appeared to be rounding into top form. ASU was coming off the crushing Oregon loss. Coach Herb Sendek has said all season a breakout – in some form – was coming, but at times it was hard to see.

Finally, he has proof.

"I'm just so happy for our players," Sendek said. "I don't want to get too mushy, but we have terrific guys. I love coaching them. We've had some tough losses, but these guys, they show up the next day. In my book that has to count for something."

UA coach Sean Miller didn't like his defense from the start, calling timeout just 55 seconds into the contest. The Wildcats built a 25-18 lead but then let ASU out-score them 23-9 over the next 10 minutes. They trailed 41-34 at halftime and couldn't get enough stops in the second half to re-take the lead.

"We did not get the job done on the defensive end, really in any way," Miller said. "Around the basket we had no rim protector, we had no physicality and it seemed a little too easy. We got beat on a number of drives (and) when we get on beat on drives, that leads to fouls, it leads to 3-point shots."

ASU shot 50 percent, just the third team to shoot 50 percent or better against UA. Barnes (18 points, 8 of 8 from the foul line) was one difference maker. Holder was another. In the first matchup, Holder was a non-factor scoring two points in 12 minutes. Saturday, he got into the lane and collected 15 points and a season-high eight assists, committing just two turnovers in 36 minutes.

"His growth over the past month has been just fantastic," Peery said. "He's grown so much and it's happened right before everybody's eyes."

Defensively, ASU's game plan was to pack the paint and force UA to win from the perimeter. The Sun Devils knew UA averaged only four 3-pointers per game in Pac-12 play, worst among conference teams. (UA went 6 of 16 from deep). They also wanted to take care of the basketball, keeping the Wildcats from getting easy looks in transition. (The Wildcats had two fast-break points).

"Hopefully, this starts something and we can finish the last half of the Pac-12 on a high note," Barnes said. "And it also just shows we're good enough to play anybody in the Pac-12 when we don't hurt ourselves."